Flash memory is an improved form of Electrically-Erasable Programmable Read-Only Memory (EEPROM). Traditional EEPROM devices are only capable of erasing or writing one memory location at a time. In contrast, flash memory allows multiple memory locations to be erased or written in one programming operation. Flash memory can thus operate at higher effective speeds than traditional EEPROM.
Flash memory enjoys a number of advantages over other storage devices. It generally offers faster read access times and better shock resistance than a hard disk drive (HDD). Unlike dynamic random access memory (DRAM), flash memory is non-volatile, meaning that data stored in a flash storage device is not lost when power to the device is removed. For this reason, a flash memory device is frequently referred to as a flash storage device, to differentiate it from volatile forms of memory. These advantages, and others, may explain the increasing popularity of flash memory for storage applications in devices such as memory cards, USB flash drives, mobile phones, digital cameras, mass storage devices, MP3 players and the like.
A host system to which a flash storage device is attached may send and receive data to and from the flash storage device in data sectors. The particular size of a data sector is usually determined by the host device. Some host devices utilize data sectors with a size of 2n bits, where n is a positive integer (e.g., 32 bits, 64 bits, 128 bits, 256 bits, 512 bits, 1024 bits, 2048 bits, etc.). Other host devices may use data sectors with non-standard sizes other than 2n bits, such as 520 bits, 524 bits, 528 bits, etc. As the size of a data segment in a flash storage device is determined at the time of manufacture, and is usually also a size of 2n bits (e.g., 1K, 2K, 4K, 8K, 16K, etc.), efficiently accommodating host devices that use non-standard data sectors presents a challenge. In this regard, storing larger, non-standard size data sectors in a flash storage device may leave a significant portion of the potential storage space thereof unused.